Method of heating asphalt pavements.



PATENTED NOV. 3, 1903.

No. 743,021. i

J. W. NESMITH &,F. 0. BLAKE. l i

METHOD 0F HEATING ASPHALT PAVEMENTS.

APPLICATION IILBD MAR. 5, 1903.

No MODEL.

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ma owns PETERS UNITED STATES Patented November 3, 1903.`

PATENT OFFICE.

JOI-IN W. NESMITH AND FRANK O. BLAKE, OF DNVER, COLORADO.

METHOD OF HEATING ASPHALT PAVEMENTS.

SPECIFICATION forming part of Letters Patent No. 743,021, dated November 3, 1903.

Application filed March 5. 1903.

To a/ZZ whom, t may concern:

Be it known that we, JOHN W. NEsivnTH and FRANK O. BLAKE, citizens of the United Sta-tes, residing at Denver, Arapahoe county, Colorado, have invented certain new and useful Improvements in Methods of Heating Asphalt Pavements, of which the following is a specification.

Our invention relates to the repairing of asphalt pavements; and it consists in the method or process of heating the .surfaces to be repaired in a thoroughly-practical manner without burning.

Prior to this invention the usual method in use has been to apply the iiame from burners directly to the surface to be treated; but this is seriously objectionable in that it destroys the integrity of the asphalt, and by the direct application of the iiame to the surface the asphalt is burned and thus spoiled. It has been proposed, but so far as we know never put into practical use, to heat air by passing it through a chamber heated externally and then passing the heated air to the surface treated; but this was impracticable by reason of the expense, only a very small percentage of the calorific value of the fuel being utilized by this proposed method.

By our method we aim to overcome the dif ficulties enumerated above as to the burning of the asphalt and the prohibitive cost by passing the air into and through a combustionchamber, the heated gaseous products passing from the chamber into contact with the surface to be treated, thus securing the maximum amount of heat with minimum cost, our method including tempering the heat of the blast as required.

In the accompanying drawing we have shown in section a simple form of apparatus by which our method may be carried out, this apparatus being identical with a form of apparatus shown in an application filed in the name of John W. Nesmitln December 27, 1902, Serial No. 136,836, and it will be understood that this is simplyrepresentative of any suitable apparatus adapted for the purpose.

The drawing shows, partly in section and partly in side elevation, an apparatus capable of carrying into effect the method made the subject of this application.

In the drawing, A is the combustion-cham- Selial No. 146,422. (No model.)

ber, E being the burner, supplied by any suitable fuel projected into the Ychamber under pressure. Air from the blower B is forced into the chamber through the conduit C and head D and finally through a series of pipes a, thus exposing the air for combustion to the heat of the chamber before being discharged into the chamber, whereby perfect combustion is secured. The heated gaseous products of combustion then pass from the chamber A through suitable gated openings b into a suitable hood F, which confines the heat and directs it to the surface to be treated.

In case the heat of the gaseous products of combustion is excessive and above, say, about 700 Fahrenheit it is necessary to modify or reduce the temperature of the gases discharged, and this we do in a very simple but effective manner by diverting a part of the blast from the fan B through the medium of a valve la directly into the combustion-chamber A through a port n, and in this way excessive heat is prevented and the outgoing blast properly tempered.

W'e of course do not limit ourselves to the apparatus shown or, indeed, to any mechan ical structure, as many modifications may be made without departing from the spirit of our invention.

1. The method hereinbefore described of heating asphaltpavements, consisting in passing a current or blast of air circuitously through a combustion-"chamber, in which a iianie is maintained under pressure, the heated products passing out of the chamber to the surface to be heated, the current or blast supporting combustion within the chamber.

2. The method hereinbefore described of heatingasphalt pavements consisting in passing a current ory blast of air circuitously through a combustiorrchamber; heating the air previous to its discharge into said chamber; utilizing the air to maintain combustion, and passing the resultant gaseous products from the chamber to the surface to be heated, substantially as described.

3. The method hereinbefore described` of heating asphalt pavements consisting in pass ing a current or blast of air circuitously through a combustion-chamber; from thence passing the products of combustion to the ICO surfaoeand modifying theheat of the `gaseous uots to the surface to be heated, substani products by admitting thereto a current of tially as described. fresh air, substantially as described. In testimony whereof We affix our signa- 4. The method hereinbefore 4described of tures in presence of two Witnesses. 5 lie'atingasphaltpavements oonsistinginmain- JOHN W NESMITIL almng a flame Wlthin a ohamber, passing a FRANK O BLAKE current or blast of air ououltously through said chamber, the oxygen thereof in Whole or Witnesses: in part being,` Combined With the burning fuel j HARPER M. OCAHOOD, Io and then passing the resultant gaseous -prod- RICHARD H.v MOORE. 

